A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
Anniversary Bulletin 1943-2013: 70 Years of Struggle... and the Struggle Continues
- Date: 2013
- Subjects: Government, Resistance to -- South Africa , South Africa -- Politics and government , South Africa -- History -- 20th century
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/37365 , vital:34158 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2013
- Date: 2013
- Subjects: Government, Resistance to -- South Africa , South Africa -- Politics and government , South Africa -- History -- 20th century
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/37365 , vital:34158 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2013
Curriculum Vitae of Prof Tebello Nyokong (OMB)
- Authors: Nyokong, Tebello
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:7233 , http://hdl.handle.net/10962/d1006180
- Description: Department of Science and Technology (DST) and National Research Foundation (NRF) Professor of Medicinal Chemistry and Nanotechnology and Distinguished Professor of Chemistry at Rhodes University.
- Full Text:
- Date Issued: 2013
- Authors: Nyokong, Tebello
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:7233 , http://hdl.handle.net/10962/d1006180
- Description: Department of Science and Technology (DST) and National Research Foundation (NRF) Professor of Medicinal Chemistry and Nanotechnology and Distinguished Professor of Chemistry at Rhodes University.
- Full Text:
- Date Issued: 2013
Finding the best clay: experiences of rural potter Alice Gqa Nongebeza contextualised
- Authors: Steele, John
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/1023 , vital:30216
- Description: When creating artefacts that belong in the material world artists choose specific raw materials for particular reasons, including that selected resources are accessible and well suited to fitness for purpose and expression of intentions. Many potters in Africa are engaged in zero electricity usage ceramics practice, and each creative cycle usually starts with extracting clay from local sites according to preferences and well established procedures that may sometimes include certain rituals. Ways in which some potters who source their own clay are particular about certain factors that are thought to be capable of influencing the effectiveness of physical properties of that raw material are explored, with particular reference to what is known about the practices of Eastern Cape potter Alice Gqa Nongebeza, of Nkonxeni Village [31°37‘59.66“S, 29°23‘22.26“E], Tombo, near Port St Johns. Specific choices enacted by potters when gathering and using clayey raw materials are considered in order to better understand some aspects of conceptual and social frameworks that may influence clay extraction procedures. Thus, by means of comparisons between particular potter’s practices, as well as through analysis of interview material and observed events, this paper aims to contextualise how it transpired, inter alia, that clay seams close to the Nongebeza homestead were ignored by her in favour of a relatively distant and almost inaccessible site that yielded a particular clay well suited to her unique firing style of placing raw ware onto an already roaring bonfire, thereby effectively creating pots for daily use and enjoyment
- Full Text:
- Date Issued: 2013
- Authors: Steele, John
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/1023 , vital:30216
- Description: When creating artefacts that belong in the material world artists choose specific raw materials for particular reasons, including that selected resources are accessible and well suited to fitness for purpose and expression of intentions. Many potters in Africa are engaged in zero electricity usage ceramics practice, and each creative cycle usually starts with extracting clay from local sites according to preferences and well established procedures that may sometimes include certain rituals. Ways in which some potters who source their own clay are particular about certain factors that are thought to be capable of influencing the effectiveness of physical properties of that raw material are explored, with particular reference to what is known about the practices of Eastern Cape potter Alice Gqa Nongebeza, of Nkonxeni Village [31°37‘59.66“S, 29°23‘22.26“E], Tombo, near Port St Johns. Specific choices enacted by potters when gathering and using clayey raw materials are considered in order to better understand some aspects of conceptual and social frameworks that may influence clay extraction procedures. Thus, by means of comparisons between particular potter’s practices, as well as through analysis of interview material and observed events, this paper aims to contextualise how it transpired, inter alia, that clay seams close to the Nongebeza homestead were ignored by her in favour of a relatively distant and almost inaccessible site that yielded a particular clay well suited to her unique firing style of placing raw ware onto an already roaring bonfire, thereby effectively creating pots for daily use and enjoyment
- Full Text:
- Date Issued: 2013
Form over function? The practical application of the Recognition of Customary Marriages Act 1998 in South Africa
- Authors: Kruuse, Helen
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54094 , vital:26389 , http://journals.co.za/content/ju_jur/2013/1/EJC148455
- Description: The Recognition of Customary Marriages Act 120 of 1998 is a major legislative measure for the development of customary marriages in line with the constitutional principle of equality, specifically for women. The article explores the interactions between this ideal in the Act with empirical observations and the latest judicial decisions concerning its application. It considers various examples of the lack of protection of women in relationships of a customary nature, and it concludes that both the state and courts favour a formal or definitional approach to customary marriage. In considering alternative approaches that could adequately protect vulnerable parties, two conclusions emerge: First, the article recommends a wholesale revision of the South African family law approach from a focus on form to dependency. Second (and as a short-term measure), the article advocates for the putative marriage doctrine to be applied in the customary marriage context to protect many women who are denied access to 'customary marriage' as a form, and as a result, all of the benefits that flow from such marriage.
- Full Text:
- Date Issued: 2013
- Authors: Kruuse, Helen
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54094 , vital:26389 , http://journals.co.za/content/ju_jur/2013/1/EJC148455
- Description: The Recognition of Customary Marriages Act 120 of 1998 is a major legislative measure for the development of customary marriages in line with the constitutional principle of equality, specifically for women. The article explores the interactions between this ideal in the Act with empirical observations and the latest judicial decisions concerning its application. It considers various examples of the lack of protection of women in relationships of a customary nature, and it concludes that both the state and courts favour a formal or definitional approach to customary marriage. In considering alternative approaches that could adequately protect vulnerable parties, two conclusions emerge: First, the article recommends a wholesale revision of the South African family law approach from a focus on form to dependency. Second (and as a short-term measure), the article advocates for the putative marriage doctrine to be applied in the customary marriage context to protect many women who are denied access to 'customary marriage' as a form, and as a result, all of the benefits that flow from such marriage.
- Full Text:
- Date Issued: 2013
Graviton multipoint functions at the AdS boundary
- Authors: Brustein, R , Medved, A J M
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: vital:6819 , http://hdl.handle.net/10962/d1004425
- Description: The gauge-gravity duality can be used to relate connected multipoint graviton functions to connected multipoint correlation functions of the stress tensor of a strongly coupled fluid. Here, we show how to construct the connected graviton functions for a particular kinematic regime that is ideal for discriminating between different gravitational theories, in particular between Einstein theory and its leading-order string theory correction. Our analysis begins with the one-particle irreducible graviton amplitudes in an anti-de Sitter black brane background.We show how these can be used to calculate the connected graviton functions and demonstrate that the two types of amplitudes agree in some cases. It is then asserted on physical grounds that this agreement persists in all cases for both Einstein gravity and its leading-order correction. This outcome implies that the corresponding field-theory correlation functions can be read off directly from the bulk Lagrangian, just as can be done for the ratio of the shear viscosity to the entropy density.
- Full Text:
- Date Issued: 2013
- Authors: Brustein, R , Medved, A J M
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: vital:6819 , http://hdl.handle.net/10962/d1004425
- Description: The gauge-gravity duality can be used to relate connected multipoint graviton functions to connected multipoint correlation functions of the stress tensor of a strongly coupled fluid. Here, we show how to construct the connected graviton functions for a particular kinematic regime that is ideal for discriminating between different gravitational theories, in particular between Einstein theory and its leading-order string theory correction. Our analysis begins with the one-particle irreducible graviton amplitudes in an anti-de Sitter black brane background.We show how these can be used to calculate the connected graviton functions and demonstrate that the two types of amplitudes agree in some cases. It is then asserted on physical grounds that this agreement persists in all cases for both Einstein gravity and its leading-order correction. This outcome implies that the corresponding field-theory correlation functions can be read off directly from the bulk Lagrangian, just as can be done for the ratio of the shear viscosity to the entropy density.
- Full Text:
- Date Issued: 2013
Obituary: John Mayne English 1922-2013
- Authors: Lewis, Colin A
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6162 , http://hdl.handle.net/10962/d1004782
- Description: In 1962 John moved south to Johannesburg, but that bustling city held few attractions for him and he moved further south, to the cathedral city of Grahamstown. Grahamstown, with its nineteenth century Gothic cathedral, elegant Georgian buildings, and distinctive grandeur of Rhodes University, St Andrew's College and other buildings designed by Herbert Baker and his colleagues, suited John. He particularly enjoyed the academic, social, artistic and dramatic life of the community, where many older members of society were distinguished old-Africa hands. John thoroughly enjoyed Grahamstown where, in the partnership of Hoskins and English, he made his mark in the restoration and extension of many significant buildings. His addition to the Anglican chapel at Hog's Back is a masterpiece, as is his incorporation of the old fayade into the rebuilding and extension of the Magistrates' Court.
- Full Text:
- Date Issued: 2013
- Authors: Lewis, Colin A
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6162 , http://hdl.handle.net/10962/d1004782
- Description: In 1962 John moved south to Johannesburg, but that bustling city held few attractions for him and he moved further south, to the cathedral city of Grahamstown. Grahamstown, with its nineteenth century Gothic cathedral, elegant Georgian buildings, and distinctive grandeur of Rhodes University, St Andrew's College and other buildings designed by Herbert Baker and his colleagues, suited John. He particularly enjoyed the academic, social, artistic and dramatic life of the community, where many older members of society were distinguished old-Africa hands. John thoroughly enjoyed Grahamstown where, in the partnership of Hoskins and English, he made his mark in the restoration and extension of many significant buildings. His addition to the Anglican chapel at Hog's Back is a masterpiece, as is his incorporation of the old fayade into the rebuilding and extension of the Magistrates' Court.
- Full Text:
- Date Issued: 2013
Prof Nyokong wins NRF Lifetime Achievement Award
- Date: 2013
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7215 , http://hdl.handle.net/10962/d1006511 , Nyokong, Tebello
- Description: Professor Tebello Nyokong of Rhodes University was presented with the Lifetime Achievement Award at this year’s NRF Awards, held in Port Elizabeth, 2013. She is currently a Distinguished Professor of Chemistry at Rhodes University and holder of the DST-NRF Research Chair in Medicinal Chemistry and Nanotechnology, as well as Director of the DST-Mintek Nanotechnology Innovation Centre focussing on sensors.
- Full Text:
- Date Issued: 2013
- Date: 2013
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7215 , http://hdl.handle.net/10962/d1006511 , Nyokong, Tebello
- Description: Professor Tebello Nyokong of Rhodes University was presented with the Lifetime Achievement Award at this year’s NRF Awards, held in Port Elizabeth, 2013. She is currently a Distinguished Professor of Chemistry at Rhodes University and holder of the DST-NRF Research Chair in Medicinal Chemistry and Nanotechnology, as well as Director of the DST-Mintek Nanotechnology Innovation Centre focussing on sensors.
- Full Text:
- Date Issued: 2013
The Essential Oil of Eucalyptus grandis W. Hill ex Maiden Inhibits Microbial Growth by Inducing Membrane Damage
- Soyingbe, Oluwagbemiga Sewanu, Oyedeji, Adebola, Basson, Albert Kortze, Opoku, Andy Rowland
- Authors: Soyingbe, Oluwagbemiga Sewanu , Oyedeji, Adebola , Basson, Albert Kortze , Opoku, Andy Rowland
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/731 , vital:29666
- Description: Eucalyptus grandis is a medicinal plant which has been indicated by Zulu traditional healer in the treatment of respira- tory tract infections, bronchial infections, asthma and cough. The investigation of the essential oil of this plant could help to verify the rationale behind the use of the plant as a cure for these illnesses. Essential oil was hydro-distilled from the fresh leaves and characterised for the chemical constituents and bioactivity. The main constituents of the oil of the E. grandis are α-Pinene (29.69%), p-Cymene (19.89%), 1,8-cineole (12.80%), α-Terpineol (6.48%), Borneol (3.48%) and D-Limonene (3.14%). The essential oil of E. grandis showed high scavenging of DPPH and ABTS radicals, and was active against 13 of the 16 organisms tested with the MIC ranging from 0.625 mg - 5.0 mg/ml; the MBC value ranged from 2.5 mg - 10 mg/ml. The essential oil also inhibited the growth of 7 of the 8 antibiotic resistant bacteria tested, with MIC ranging from 5 mg/ml - 10 mg/ml. The DNA extracted from the affected microorganisms did not show any dam- age however, there was an increase of released cytosolic LDH activity. We conclude that the antibacterial activity of the essential oil was exhibited through cell membrane damage rather than the damage of the DNA. It is apparent that the bioactivity of the essential oil of E. grandis plays an important role in the plants’ use in folk medicine for the treatment of respiratory tract illnesses.
- Full Text:
- Date Issued: 2013
- Authors: Soyingbe, Oluwagbemiga Sewanu , Oyedeji, Adebola , Basson, Albert Kortze , Opoku, Andy Rowland
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/731 , vital:29666
- Description: Eucalyptus grandis is a medicinal plant which has been indicated by Zulu traditional healer in the treatment of respira- tory tract infections, bronchial infections, asthma and cough. The investigation of the essential oil of this plant could help to verify the rationale behind the use of the plant as a cure for these illnesses. Essential oil was hydro-distilled from the fresh leaves and characterised for the chemical constituents and bioactivity. The main constituents of the oil of the E. grandis are α-Pinene (29.69%), p-Cymene (19.89%), 1,8-cineole (12.80%), α-Terpineol (6.48%), Borneol (3.48%) and D-Limonene (3.14%). The essential oil of E. grandis showed high scavenging of DPPH and ABTS radicals, and was active against 13 of the 16 organisms tested with the MIC ranging from 0.625 mg - 5.0 mg/ml; the MBC value ranged from 2.5 mg - 10 mg/ml. The essential oil also inhibited the growth of 7 of the 8 antibiotic resistant bacteria tested, with MIC ranging from 5 mg/ml - 10 mg/ml. The DNA extracted from the affected microorganisms did not show any dam- age however, there was an increase of released cytosolic LDH activity. We conclude that the antibacterial activity of the essential oil was exhibited through cell membrane damage rather than the damage of the DNA. It is apparent that the bioactivity of the essential oil of E. grandis plays an important role in the plants’ use in folk medicine for the treatment of respiratory tract illnesses.
- Full Text:
- Date Issued: 2013
Vrou is gif : the representation of violence against women in Margie Orford’s Clare Hart novels
- Authors: Naidu, Samantha
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:26372 , http://hdl.handle.net/10962/53997 , https://www.ajol.info/index.php/asp/article/view/136092 , https://orcid.org/0000-0001-9456-8657
- Description: This article takes as its starting point that crime fiction is a public and political response to gender-based violence. Using the methods of both discourse analysis and literary analysis of the crime fiction genre, the novels of Margie Orford, internationally acclaimed crime author and patron of Rape Crisis, are examined for their representations of violence against women, and the role played by these representations in Orford’s overall feminist project in the Clare Hart series. The article also considers theories about gender-based violence which link male violence to a purported crisis in the established gender order of South Africa. An attempt is made to understand the relationship between fictionalised representations of violence and the ‘banality’ of real-life violence. Finally, Hart, Orford’s hard-boiled female detective figure, is assessed to determine whether this character constitutes a significant feminist achievement that contributes to discourses which counter gender-based violence
- Full Text: false
- Date Issued: 2013
- Authors: Naidu, Samantha
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:26372 , http://hdl.handle.net/10962/53997 , https://www.ajol.info/index.php/asp/article/view/136092 , https://orcid.org/0000-0001-9456-8657
- Description: This article takes as its starting point that crime fiction is a public and political response to gender-based violence. Using the methods of both discourse analysis and literary analysis of the crime fiction genre, the novels of Margie Orford, internationally acclaimed crime author and patron of Rape Crisis, are examined for their representations of violence against women, and the role played by these representations in Orford’s overall feminist project in the Clare Hart series. The article also considers theories about gender-based violence which link male violence to a purported crisis in the established gender order of South Africa. An attempt is made to understand the relationship between fictionalised representations of violence and the ‘banality’ of real-life violence. Finally, Hart, Orford’s hard-boiled female detective figure, is assessed to determine whether this character constitutes a significant feminist achievement that contributes to discourses which counter gender-based violence
- Full Text: false
- Date Issued: 2013
You reap what you sow : regulating marriages and intimate partnerships in a diverse post-apartheid society
- Authors: Kruuse, Helen
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54152 , vital:26396 , https://tinyurl.com/yaughtn2
- Description: South Africa does not have a particularly proud history. Marred by the politics of separate but (un)equal treatment of its people, the country's past political system has had a damaging effect in all spheres, but specifically on that of the family. In the context of relationships, it is fair to say that the apartheid system was replicated in family law, with the Western 'white' monogamous marriage receiving the state's stamp of approval - leaving other relationships (customary, Muslim, homosexual, cohabiting etc) largely out in the cold.
- Full Text:
- Date Issued: 2013
- Authors: Kruuse, Helen
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54152 , vital:26396 , https://tinyurl.com/yaughtn2
- Description: South Africa does not have a particularly proud history. Marred by the politics of separate but (un)equal treatment of its people, the country's past political system has had a damaging effect in all spheres, but specifically on that of the family. In the context of relationships, it is fair to say that the apartheid system was replicated in family law, with the Western 'white' monogamous marriage receiving the state's stamp of approval - leaving other relationships (customary, Muslim, homosexual, cohabiting etc) largely out in the cold.
- Full Text:
- Date Issued: 2013
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